Hurricane Sandy has scrambled the last week of the presidential race, upsetting campaign schedules, putting both President Obama and Mitt Romney off-message, and raising doubts about Election Day. In a race this close, Sandy could change or at least postpone the results.

It’s not out of the question that the hurricane – a massive and unusual storm event forecast to rip into the Atlantic coast from the Del-Mar-Va peninsula to New England before barreling west across New York State and Pennsylvania en route to the all-important swing state of Ohio – could directly affect the outcome, changing or at least postponing the results.

Maryland already has canceled early voting Monday, per Gov. Martin O’Malley’s order Sunday. Faced with power outages that could last several days, the Virginia state elections board is planning for extended early voting hours.

Both candidates have had to adjust their last-minute campaign travel plans.

Obama canceled campaign stops Monday in Virginia and Tuesday in Colorado to monitor the storm but planned to go forward with other events Monday in Florida and Ohio, with former president Bill Clinton at his side, AP reports. Romney cut three stops in Virginia on Sunday, opting instead to campaign with running mate Paul Ryan in Ohio before heading Monday to Wisconsin, where the former Massachusetts governor has chipped away at Obama’s lead.

TV ads can have more impact than cheerleading events with the faithful; they’ll continue as long as there’s electrical power. Both sides are flush with cash in this billion-dollar campaign.

But an “October surprise” like this – particularly in a very close race where the challenger has been gaining on the incumbent – has the potential to do more damage to Obama than to Romney.

All the GOP candidate has to do is avoid the appearance that he’s taking political advantage of a potential tragedy – something he failed to do during the early hours of the terrorist attack on the US consulate in Benghazi, Libya.

But if things go wrong with the federal response to Sandy, Obama will be blamed. And the Obama camp in particular is counting on early voters and get-out-the-vote efforts come Election Day.

"Obviously we want unfettered access to the polls because we believe that the more people that come out, the better we'll do," top Obama adviser David Axelrod said on CNN Sunday. "And so, to the extent that it makes it harder, that's a source of concern."

"I hope that it all clears out and by the next weekend, we'll be free of it,” Axelrod added

Political scientists believe natural disasters can hurt an incumbent's reelection chances as voters often blame whoever is in office for adversity, Reuters reports.

“Larry Bartels of Vanderbilt University and Christopher Achen of Princeton University examined rainfall data back to 1896 and found that extreme droughts or floods cost the incumbent party office holders an average of 1.5 percentage points of the vote total,” Reuters reported Sunday. “Severe drought and excessive rainfall probably cost then Vice President Al Gore victories in seven states in the 2000 election, enough to hand the contest to Republican George W. Bush, they found.”

Five years later, President Bush's approval ratings plummeted after Hurricane Katrina devastated New Orleans, and voters could similarly blame Obama if the government fumbles its response to this storm. A fraction of a percentage point here or there, as Bartels and Achen reported, could swing a state’s popular vote enough to change the results in the all-important Electoral College.

As all eyes were on Sandy, new poll data confirmed the closeness of the race.

“The race for the White House continues to be too close to call in Ohio, according to a new Enquirer/Ohio News Organization Poll that shows President Barack Obama and Mitt Romney each with 49 percent support from likely voters,” the Cincinnati Enquirer reported Sunday. “That’s a slip for the president, who took 51 percent of likely voters in the newspaper group’s September poll.”

Said Eric Rademacher, co-director of the University of Cincinnati’s Institute for Policy Research, which conducted the poll: “Absent any more twists and turns, a remarkable presidential campaign may end with the campaign that executes the best ‘ground game’ narrowly delivering Ohio for the next president of the United States.”